First, battles are turn based.
To decide who goes first each player rolls one 100 sided die. (see post action in message options at top)
The player with the higher number attacks first.

Attack setup looks like this
Attack dmg + any bonuses + strength - opponent defence = DMG

Oh, and also you can not use the same attack twice within 3 turns of itself. Otherwise People use the same move over and over and it get boring.

Special Attacks never miss and can only be used once per fight.

heres how you stats work:
Health- whenever you take dmg, subtract it from this. you lose at zero health
Energy- this is spent to use attacks and abilities.
Strength- for every 1 point in this you add 10 dmg to attacks
Defense- for every 1 point in this your opponent takes 10 dmg off their attacks
Speed/Agility- you can spend 1 point from this to try and dodge an attack*

*to dodge an attack you roll a 6 sided die and if the result is an even number you dodge the attack.